What's a good estimate on the nominal density of loose tea?

I don't think getting a mass/volume ratio from a wholesale tea-chest
would be a good answer, because those things look pretty tightly
packed.

Optimally, I should be able to measure the volume of a rigid container
and know with 95% certainty how much tea I can put in it without fear
of spillage the first time I spoon some out.

--Blair